en Copyright 2015 Java http://172.16.0.5:8080/history/llvm-project-15.0.7/llvm/test/tools/llvm-profdata/Inputs/function-entry-coverage.profdata#11d30742 [InstrProf] Add single byte coverage modeUse the llvm flag `-pgo-function-entry-coverage` to create single byte "counters" to track functions coverage. This mode has significantly less size overhead in both code and data because * We mark a function as "covered" with a store instead of an increment which generally requires fewer assembly instructions * We use a single byte per function rather than 8 bytes per blockThe trade off of course is that this mode only tells you if a function has been covered. This is useful, for example, to detect dead code.When combined with debug info correlation [0] we are able to create an instrumented Clang binary that is only 150M (the vanilla Clang binary is 143M). That is an overhead of 7M (4.9%) compared to the default instrumentation (without value profiling) which has an overhead of 31M (21.7%).[0] https://groups.google.com/g/llvm-dev/c/r03Z6JoN7d4Reviewed By: kyuleeDifferential Revision: https://reviews.llvm.org/D116180 List of files: /llvm-project-15.0.7/llvm/test/tools/llvm-profdata/Inputs/function-entry-coverage.profdata Thu, 27 Jan 2022 19:22:43 +0000 Ellis Hoag <ellis.sparky.hoag@gmail.com>